QUESTION: Cpk can be used to short term capability and Ppk used to long term capability. However, there are references confirming this idea and there are references saying the opposite. What do you think? RESPONSE: Cpk and Cp are a function of how the data are collected and can be very deceiving. For example, if [...]
Posts Tagged ‘Cpk’
Process capability (Cp, Cpk, Pp, Ppk) deceptions and resolution
It has been said that Cpk can be used to short term capability and Ppk used to long term performances. However, is there more to the story?
Six Sigma level metric, issues and resolution
QUESTION: Cp and Cpk: Is the Sigma Level 3 times the Cp value or 3 times the Cpk value? One person said Sigma Level is three times the CpK value. Another person said when you talk of Sigma Value you apply the 1.5 sigma shift (standard introduced by Motorola and widely accepted). On the other [...]
Enhancement to Cp, Cpk, Pp, and Ppk capability indices
QUESTION: Of the capability indices Cp, Cpk, Pp, and Ppk, which is rarely or no longer used and why? RESPONSE: The methodology to calculate Cp, Cpk, Pp, and Ppk are quite simple but did you know that the calculated value for these indices are a function of the sampling and control charting procedure that was [...]
Lean Six Sigma process capability sigma quality: Issues and resolution
QUESTION: Thoughts about calculating an overall sigma level for an organization using a scorecard approach?
